The proposed K23 Patient-Oriented Career Development Award is designed to provide the PI with the training necessary to study the individual variability in bio-behavioral consequences of appearance and performance enhancing drug (APED) use. Candidate: The PI is an Assistant Professor and licensed clinical Psychologist currently working at the Mount Sinai School of Medicine's (MSSM's) Eating and Weight Disorders Program. He plans to use the K23 to become an R01 funded researcher that works closely with basic and translational scientists on the clinical, ethical, and scientific challenges presented by APED use. In order to obtain these career goals, he will use the K23 to acquire knowledge, skills, and abilities necessary to the study the relationship between endocrine/neuroendocrine function and aggression/impulsivity among APED users. His specific training objectives are to (a) learn the theoretical, methodological, and clinical approaches to studying the distinction between pathological and non-pathological forms of APED use, (b) develop a working knowledge of the theory and methodology available through translational research to study hormone-behavior relationships, (c) acquire expertise in the theory and methodology linking hormone dysregulation to psychiatric illness, (d) acquire greater understanding of the medical, legal, and ethical issues associated with studying substance abuse, and (e) obtain expertise in longitudinal data modeling and statistical analysis of biological data. Environment: The Pi's proposed training plan and career goals are consistent with the MSSM Department of Psychiatry's mission statement to integrate translational and clinical research, particularly in the area of neuroendocrinology. Dr. Hildebrandt has available to him a wealth of expertise and resources available including the lab facilitates necessary to study both endocrine and neuroendocrine functioning. Research: The most reliable psychiatric consequence to APED use is increased impulsive aggression although a range of psychiatric disturbances have been observed. The supervised research project will be a longitudinal study of the degree of both hormone and psychiatric dysregulation (aggression and impulsivity) in 60 adult male APED users across time (on-cycle and off-cycle) compared to 20 age, exercise, and education matched controls. Piecewise latent growth curve modeling will be used to investigate changes on-cycle and off-cycle changes and the following predictors of change will be explored: APED characteristics (amount, duration, and pattern), Age, Psychiatric History, Personality, &History of APED use). Relevance: Findings from the proposed study will help identify both the endocrine dysfunction responsible for the psychiatric consequences to APED use and the user characteristics predictive of these psychiatric consequences. Implications of this research are to inform prevention, intervention, and policy based decisions related to this growing public health concern.